Today nearly four million people have been born thanks to in vitro fertilization, which occurs when sperm is injected into an egg cell outside the body and the resulting embryo is implanted back into the womb. (Watch a video of how in vitro fertilization works.)

Edwards first envisioned IVF during the 1950s and went on to develop and hone the technique in the 1960s and '70s.

He achieved his first success on July 25, 1978, when Louise Brown, the world's first "test-tube baby" was born in the United Kingdom.

"The development of IVF has enabled many millions of couples to have a child who might not otherwise have been able to," he said in a telephone interview.

The Nobel Assembly at Sweden's Karolinska Institute, which awarded the 10-million-Swedish-krona (1.5 million-U.S.-dollar) prize, described IVF as a "milestone of modern medicine, which brings joy to infertile people all over the world."

Robert Edwards was too ill to speak to the media about his award, Nobel committee member Goran Hansson told a news conferencein Stockholm Monday.

But, Hansson added, "I spoke to his wife, and she was delighted. She was sure he would also be delighted."

Birth of a Nobel-Worthy Technique

More than 10 percent of couples worldwide are infertile. In the past medical help was limited, but today IVF therapy results in successful births for roughly one in five of every fertilized egg implanted.

The odds for a healthy couple conceiving naturally are about the same.

Edwards's initial inspiration came from the work of other scientists, which showed that egg cells from rabbits could be fertilized in test tubes when sperm was added.

The scientist realized that this could be a potential treatment for human infertility and began to experiment with human egg cells.

At this point controversy erupted, with opposition to the technique coming from religious leaders and various governments. The U.K.'s Medical Research Council decided not to continue funding the project.

However, a private donation enabled the pair to continue their research, which ultimately led to their first complete success—Louise Brown's birth.

Since 1978 the technique has been further refined, resulting in easier and more comfortable methods of egg removal.

However, in vitro fertilization treatments often lead to multiple pregnancies, which can pose risks to both the babies and the mother. For instance, multiple pregnancies can increase the likelihood for premature delivery and low birth weight, according to the University of Maryland Medical Center.

Even so, "IVF is here to stay," said University Hospital's Kennedy.

"I expect it will be combined with genetic screening in the future, to lessen the likelihood of inherited diseases, and there will be refinements to improve the success rates and reduce the chances of multiple births."